Glass containers and the like, produced from soda lime glass, have been and are in great demand because of their many beneficial attributes. However, after use they are subject to breakage and great difficulty has been encountered in the disposal or reclamation of such glass. Ecological factors have been carefully considered by the glass container industry. Nonetheless, heretofore great difficulty has been encountered in the disposal or further use of soda lime glass when it is used or broken. The sole major method of using waste glass is re-melting. The glass industry currently collects about 3% waste glass and purchases, through dealers, a further 10% of waste glass for its production needs. However, re-melting requires color sorting and cleaning of the waste glass. For economic reasons, glass recycling by re-melting is only of limited feasibility. Furthermore, ecological problems have existed in connection with the use of other waste materials such as waste bricks, fly ash, waste perlite, some metal, and other scrap material.
As a consequence there was a long standing and well recognized need for a process by which such materials as soda lime glass, with its many advantageous properties, could be the subject of further beneficial use after its first use in containers, window glass or other forms.
In addition, building construction shapes, such as common brick produced in brick kilns, cement bricks, concrete blocks, cinder blocks, ornamental tile, roofing tile, backup brick and tile, sills, lintels and such other shapes of special dimension and configuration as may be required in building construction, are produced by combining their ingredients, such as sand, shale, clay, cement, aggregate, water, coloring matter, and so forth, in desired proportions. The batch is then mixed and formed into the desired shape by pressing, casting, mechanical molding, or extrusion, and finally hardening the shape by heating or air curing to produce the desired strength. As is well known to the art, some of the described construction shapes are fired at relatively high temperatures, in the range of from 2000.degree.F to 2600.degree.F as in the case of building brick, to bring about the necessary chemical and physical reactions among the ingredients of the shape in order to achieve bonding. In other instances, as in the case of concrete blocks, cinder blocks and concrete pipe, air curing or "setting up" is all that is required for strength development. However, none of the processes for the manufacture of fired construction shapes has hithertofore succeeded in producing a desired form at a relatively low firing temperature which combines compressive and tensile strengths greater than those of concrete with the ornamental properties of construction shapes.